6.3 Periodic Trends

half the distance between the nuclei of two atoms of the same element when the atoms are joined

atomic radius

at atom or group of atoms that has a positive or negative charge

ion

In general, how can the periodic trends displayed by elements be explained?

the trends can be explained by variations in atomic structure.

Elements with a high electronegativity value tend to form positive ions. (True/False)

False

When do ions form?

Ions form when electrons are transferred between atoms.

How does atomic size change within groups and across periods?

Atomic size generally increases within a group and decreases from left to right across oa period.

An anion has more electrons than protons (True/False)

True

Removing one electron from an atom results in the formation of a positive ion with a 1+ charge (True/False)

True

For the following pairs of atoms, tell which one of each pair has the largest ionic radius a. Al, B b. S, O c. Br, Cl d. Na, Al e. O, F

a. Al b. S c. Br d. Na e. O

Indicate which element of the following pairs is the most electronegative. a. calcium, gallium b. lithium, oxygen c. chlorine, sulfer d. bromine, arsenic

a. gallium b. oxygen c. chlorine d. bromine

a negatively charged ion

anion

Compare the size of ions to the size of atoms from which they form

anions are larger and cations are smaller than the atoms from which they form.

a positively charged ion

cation

Atomic radii generally _______ as you move from left to right in a period.

decreases

How does electronegativity vary within groups and across periods?

decreases from top to bottom within a group and increases from left to right across a period.

the ability of an atom of an element to attract electrons when the atom is in a compound

electronegativity

The ability of an atom to attract electrons when it is in a compound is called ________. This value ________ as you move from left to right across a period.

electronegativity increases

Ions form when _________ are transferred between atoms.

electrons

Ionization energy generally _________ as you move from left to right across a period.

increases

Atomic size ________ with atomic number within a group because there are more occupied _______ and an increased shielding effect, despite an increase in nuclear __________.

increases energy levels charge

The energy required to remove an electron from an atom is known as __________ energy.

ionization

the energy required to remove an electron form an atom in its gaseous state

ionization energy

Cation are always ___________ than the atoms from which they form.

smaller